To date, vehicles have included left and right front side frames each disposed on the left and right sides of the vehicle front portion and extending in the front-and-rear direction of the vehicle body (for example, refer to Japanese Patent No. 3400566 (paragraph [0019] and FIGS. 1 and 5) and Japanese Unexamined Patent Application Publication No. 2008-137507 (FIGS. 1, 2, and 4).
Japanese Patent No. 3400566 discloses a vehicle front portion structure that prevents a power unit from entering a vehicle room. The structure has front side frames each branching into an upper frame and a lower frame; when the vehicle is involved in a frontal collision, front members mounted on the lower frames push up the front part of the power unit so as to rotate the power unit, whereby the power unit falls under a toe board.
With such a structure described above, since the lower frames of the front side frame, which each branch into a substantially Y-shape toward the front of the vehicle, are inclined downward toward the front, the branching parts can be bent downward and the power unit may easily fall not to enter the vehicle room.
Japanese Unexamined Patent Application Publication No. 2008-137507 discloses another vehicle front portion structure. This structure has front side frames each branch into a plurality of interconnecting members in which the vicinity of respective suspension towers. A load caused by a frontal collision and applied to the front side frames can be distributed among front pillars.
With such a vehicle front portion structure, when the vehicle is involved in a severe frontal collision, since the collision load applied to the front side frames is transferred to the top and bottom of the front pillars via the plurality of the interconnecting members, the collision load can be distributed.